Pressure loaded pump



March 5, 1968 PETTYJOHN ET AL 3,371,615

PRESSURE LOADED PUMP Original Filed Aug. 15, 1966 4 Sheets-Sheet 1 17 \fiz/ezz 501's Owiz'zz 5P6 iffy/01422,

Fulfil rffillfileti, Fobefi F.pa1 Zc[502z Jamas E. Cox

March 5, 1968 A. E. PETTYJOHN ET AL 3,371,615

Original Filed Aug. 15, 1966 4 Sheets-Shet 2 Pul /Z apt-Mia,

- Fobezi' aja/t'daon zfamas'fi C076 514515522 Z 652 join,

March 5, 1968 A. E. PE-TTYJOHN ETAL 3,371,615

PRESSURE LOADED PUMP Original Filed Aug. 15, 1966 4 Sheets-Sheet 4 fidezzfors 01495112 l. Peizy 'ofzzz, Ralph rIRibZe 2,

P017612 )2 flaflz'a s'ozz James F. Cox

United States Patent C) 3,371,615 PRESSURE LOADED PUMP Austin E. Pettyjohn, Auburn, Ind., Ralph J. Riblett, Wooster, and Robert R. Davidson, Elyria, Ohio, and James R. Cox, Fort Wayne, Ind., assignors to Borg- Warner Corporation, Chicago, Ill., a corporation of Illinois Continuation of application Ser. No. 572,494, Aug. 15, 1966. This application Jan. 16, 1967, Ser. No. 609,686

12 Claims. (Cl. 103-126) ABSTRACT OF THE DISCLOSURE An improved pressure loaded pump having a one-piece wear plate mounted between the pump gears and the housing. The Wear plate has a groove on the face adjacent the pump end wall which is of a spectacle shape and in which is assembled a sealing member and a resilient member. Fluid pressure in the groove urges the sealing member into contact with the end wall to define pressure loading Zones on the wear plate.

This application is a continuation of my earlier-filed patent application, Ser. No. 572,494, filed Aug. 15, 1966, entitled, Pressure Loaded Pump.

It is an object of the present invention to provide an improved pressure loaded pump utilizing a wear plate having an improved sealing means therein to accomplish the necessary sealing for pressure loading.

It is a more particular object to provide an improved pump mechanism including a wear plate having a relatively thin cross section with grooves formed in the wear plate having sealing means within the groove. The invention may be used for example in gear type pumps with the wear plate mounted between the side faces of the gears and an end Wall of the pump body. The grooves in the wear plate are preferably formed on the face of the wear plate adjacent the pump end wall and the grooves have a seal therein in sealing engagement with the end Wall of the pump to define pressure loading zones around the wear plate.

The improved sealing structure comprises a sealing member which may be composed of a synthetic nonmetallic material within the grooves in the wear plate. Below the sealing member is mounted a resilient member which forms a pressure channel in the grooves in which fluid pressure will be supplied when the pump is operating to compress the resilient member and force the sealing means outwardly from the wear plate into engagement with the pump end wall to seal the pressure loading zones and further to aid in the pressure loading by providing additional force moving the wear plate toward the pump gears.

Further, the present invention includes a resilient means in the groove in the pump wear plate having projections thereon which are compressed when the pump is assemblied so that after assembly the wear plate is preloaded into engagement with the pump gears to provide necessary pump efficiency when the operation of the pump is initiated,

Other objects and advantages of novel features of the invention will become apparent upon consideration of the detailed description in connection with the accompanying drawings wherein:

FIGURE 1 is a top view of a pump embodying the principles of the present invention;

FIGURE 2 is a cross sectional view taken along the line 2-2 of FIGURE 1;

FIGURE 3 is a sectional view taken along the line 33 of FIGURE 1;

3,371,615 Patented Mar. 5, 1968 FIGURE 4 is a sectional view taken along the line 44 of FIGURE 1;

FIGURE 5 is a cross sectional view taken along the line 55 of FIGURE 3;

FIGURE 6 is a sectional view taken along the line 6--6 of FIGURES;

FIGURE 7 is an end view of the wear plate for the P p;

FIGURE 8 is an end view of the opposite side of the wear plate and the pump;

FIGURE 9 is an end view of the wear plate of FIG- URE 8;

FIGURE 10 is a view of the resilient means for the wear plate grooves;

FIGURE 11 is a cross sectional view taken along the lines 1111 of FIGURE 8;

FIGURE 12 is a cross sectional view taken along the lines 1212 of FIGURE 10;

FIGURE 13 is a view of a modified form of wear plate design;

, FIGURE 14 is an end view of the wear plate of FIG- URE 13 partially in cross section;

FIGURE 15 is a cross sectional view taken along the line 15-15 of FIGURE 13; and

FIGURE 16 is a cross sectional view taken along the line 1616 of FIGURE 13.

Referring to FIGURES 1 and 2 a pump is illustrated which may employ the present invention therein. The pump 10 includes a pump body or housing 11 and a pump end cover 12. The pump body 11 includes a cavity 25 defined by an inner peripheral surface 25a. Mounted within the pump cavity are gears 13 and 14 which intermesh and when rotated are operative to pump fluid. Journals 16 are provided for the gears 13 and 14. One of the journals 16 for the gearing includes an extension 17 having a keyway 18 therein engageable by a key 19 to provide the driving connection to turn the pump gears when connected to a power source. The journals 16 for the gears 13 and 14 are mounted in a pair of bores 20 within the cover 12 and in a pair of bores 21 provided in the pump body 11. Holes 26 are provided in the pump body 11 for mounting the pump in a desired position. The cover member 12 may be secured to the pump body 11 by any known means as for example by bolts 27. An improved wear plate 30 is provided which is mounted in the pump cavity between the gears 13 and 14 and an inner face or wall 31 of pump body 11. The gears 13 and 14 have side faces 32 which are engaged by the wear plate 30.

Referring to FIGURES 4 and 5 an inlet port 35 is shown in the cover 12 which communicates fluid into the cavity 25 of the pump body.

Referring to FIGURES 1 and 3 an outlet port 36 for pressure developed by the pump 10 is illustrated which is formed in the pump body 11. The outlet port 36 could also be located in the cover member 12 as indicated in phantom lines in FIGURES 4 and 5.

Referring to FIGURE 4 the bores 20 in the cover 12 which receive journals 16 of the pump gears are provided with counter bores 38. Counter bores 38 comprise a chamfered recess in communication with grooves 39 which extend axially the length of the bores 20. The grooves 39 serve to supply lubricant to the journals within bores 20. Likewise referring to FIGURE 6 the bores 21 on pump body 11 which accommodate journals 16 of the pump gear may be counter bored to form recesses 41. The recesses 41 communicate with grooves 42 which extend axially along the bores 21 to carry lubricating fluid to the journals 16.

Referring to FIGURE 4 the cover 12 is provided with a generally pear-shaped recess 45 and a generally rectangular outlet recess 46. The outlet recess 46 is provided with connecting arcuate recesses 47.

Referring to FIGURE 7 the wear plate 30 is also provided with a rectangular shaped inlet recess 48 and a partially rectangular outlet recess 49. The relationship between the recesses is best illustrated in the cross section of FIGURE 5. The inlet recesses 45 and 48 combine to provide adequate and smooth flow of fluid to the pump gears. The outlet recesses 46 (with arcuate recesses 47) and 49 prevent the fluid from being trapped between the teeth of the gears and thus prevent undue high pressure from being developed in excess of the pressure normally obtained from the pump.

As illustrated in FIGURES 3, and 6 the cavity for the gears 13 and 14 includes an axially extending recess 51 connected to the inlet of the pump and an axially extending outlet recess 52 connected to the outlet of the pump 36. The recesses 51 and 52 extend axially parallel to the axis of rotation of the gears 13 and 14 and insure adequate fluid flow to and from the pump gears.

A pocket 54 defined by an inner peripheral surface 54a is formed within the pump body 11 on the side opposite cover 12 which contains the inner face 31. The wear plate 30 of the pump is mounted within pocket 54; The pocket 54 includes projecting areas 55 and 56 which project into the pocket 54 on opposite sides thereof. The projecting areas 55 and 56 have different shapes, the area 55 being rather blunt and the area 56 more pointed. The purpose of the shape of areas 55 and 56 will be described later.

Referring to FIGURES 7, 8 and 9 the wear plate 30 for the pump containing the novel pressure loading and sealing structure of the present invention is illustrated. The wear plate 30 has a face 60 which is adapted to engage the gear side faces 32. Also, the wear plate has a face 61 on the opposite side thereof adapted to be in close association with the inner face 31 of the pump body. The wear plate 30 is generally of a figure 8 shape having two generally circular sections.

The outer circumference of the wear plate 30 is relieved to define circumferential outer peripheral portions 65 of reduced radius as compared with body engaging portions 66.

The wear plate 30 includes central bores 68 and 69 adapted to receive the journals 16 of the gears 13 and 14. The bores are somewhat larger than the journals of the gears forming clearances 68b and 69b so that the wear plate 30 may move transversely with respect to the axis of the gears to a limited extent.

The shape of the wear plate in the central area thereof differs as illustrated in FIGURES 7 and 8. These areas have a different shape so as to correspond to the areas 55 and 56 provided in the pump cavity 25. Thus the wear plate can be assembled into the cavity 25 in one relationship only to the cavity thereby insuring the wear plate will be assembled with the face 61 toward the inner face 31 of pocket 54 and the face 60 toward gears 13 and 14. Therefore a generally straight line area 70 is provided on wear plate 30 which generally matches projecting area 55 of pump cavity 25 and a generally circular indented area 71 is provided on the opposite side of wear plate 30 which generally matches the shape of projecting area 56.

Provided on the face 60 of wear plate 30 surrounding the bores 68 and 69 are recesses 73. Connected to recesses 73 are vertically extending recesses 74 which serve to conduct fluid from near the intermeshing area of the pump gears to the recesses 73 which will thus insure that the internal bores 68 and 69 have adequate fluid for lubrication and cooling during operation of the pump.

Provided in the face 61 of the Wear plate 30 is a continuous groove 77 which generally is of a spectacle shape surrounding each of the journals for the gears and including generally straight sections 78 and 79 which extend from the circular portions of the groove surrounding bores 68 and 69 out to the circumferential portions 66. Extending radially from the groove 77 are grooves 79 which in a preferred embodiment of the pump are four in number adapted to convey fluid to the groove 77. The grooves 79 extend from the groove 77 to the circumferential portions 65 of the wear plate 30.

Assembled within groove 77 are two components having generally the same spectacle shape as groove 77. A resilient member or elastomer 80 is assembled within groove 77 and on top of the resilient member 80 is a sealing member 81 also assembled within groove 77.

Referring to FIGURES 10 and 12 the elastomer or resilient member 80 is illustrated. The resilient member 80 has a plurality of generally conical projections 85 on one side thereof. On the opposite side of projections 85 is a face 86. Conical projections 85 are distributed over the entire extent of resilient member 80 in equidistance locations. The conical projections 85 function as a preloading means for the wear plate 30 as will be later described. The resilient member 80 may be composed of rubber or similar types of elastomers.

The spectacle shaped sealing member 81 is of a generally rectangular cross section which will closely match the width of the groove 77 as it is assembled in groove 77 As illustrated in FIGURE 11 the sealing member 81 is adapted to engage the inner face 31 of the pocket 54 in the cavity 25 of the pump.

With the seal member 81 engaging the face 31 pressure zones are defined on the wear plate 30 and within the pocket 54 in which the wear plate 30 is disposed. A low pressure area is defined which is generally in the area of inlet recess 51 and on the inlet side of the pump. A high pressure area 91 is defined which extends around the major portion of the wear plate 30. The defined high pressure area 91 is in communication with the outlet or high pressure recess 52 of the pump. The area 91 is so shaped and defined so as to properly pressure load the pump to counterbalance the forces developed in the high pressure outlet zone of the intermeshing gears 13 or 14 adjacent the wear plate. Due to the clearance between the projecting area 56 within pump cavity 25 and the wear plate 30 the high pressure in the outlet recess 52 is communicated around the circumferential portions 65 of the wear plate to the face 61 and to the high pressure defined zone 91.

High pressure in the area 91 of the wear plate is conducted by grooves 79 into the groove 77. High pressure in groove 77 applies force to the elastomer 80 thereby deforming same and forcing face 86 of the elastomer or resilient member 80 into engagement with sealing member 81 to urge same outwardly of the wear plate 30 into engagement with inner face 31. A pressurized fluid seal is thus provided to insure that the pressure zones on the wear plate and within the pocket 54 will be maintained. Thus as the pressure within the pump increases the force of the resilient member 80 on the sealing member 81 also increases. The pressurized fluid seal which surrounds the journals 16 of the pump also prevents air from being sucked along journals 16 into the inlet by inlet vacuum and thereby prevents the poor efliciency which can result when this type of seal is not provided.

When the pump is assembled the height of conical projections 85 is such that the projections engage the lower or bottom surface of the groove 77 and are compressed slightly in assembly. Thus the conical projections 85 provide a preload for the sealing member 81 urging the sealing member 81 into engagement with inner face 31 prior to any pressure being developed by the pump. Since the groove 77 is continuous the high pressure communicated through grooves 79 will be communicated around the entire extent of the groove 77 so that sealing member 81 is urged into engagement with inner face 31 with a relatively constant force over its entire extent.

Due to the relieved portions 65, the fluid pressure acting on the wear plate 30 in the high pressure zone is generally constant over most of its extent. This type of relieving helps alleviate the pressure gradient changes due to speed variation. At high speeds the seal point between the gear teeth and body bore tend to move towards the outlet port whereas at low speeds it tends to move towards the inlet. Only in the area of portions 66 of relatively small arcuate extent is a pressure gradient involved thereby improving the pressure loading characteristics of the pump.

When the pump is delivering high pressure, the wear plate 30 will be urged into engagement with the face 60 of the wear plate engaging face 3 2 of gears 13 and 14. The high pressure is not only utilized to pressure load the pump but will act on the circumferential portions 65 of the wear plate due to the clearance involved between these areas and the pocket 54 and move the wear plate transversely so that areas 66 engage the cavity 25 and provide a fluid seal between areas 66 and cavity 25. This seal being necessary to prevent fluid pressure from being communicated between the high pressure area 91 on wear .plate 30 and low pressure area 90. Since only area 66 engages the bore 25 the improved wear plate 30 is economical to manufacture in that only the area 66 on the outer circumference thereof need to be finish machined.

The sealing members 8 1 are constructed to relatively closely engage either side of groove 77 to prevent the possibility of the elastomer 80 from being extruded out of groove 77 under high pressure between the wear plate 30 and the inner face 31 which would destroy the effectiveness of the fluid seal.

Referring to FIGURES 13, 14, 15 and 16 a modified form of wear plate is illustrated. The wear plate 30a is generally similar in construction to wear plate 30. The identical portions of wear plate 30a are numbered the same as wear plate 30 with the suffix small a added. The difference being that in the modified wear plate 30a a groove 77a is utilized which is of a generally W configuration although the groove 77a of wear plate 30a may also be referred to as of a generally spectacle shaped configuration. As compared to the groove 77 of wear plate 30 an area of the seal which would complete the incircling of the bores 68 and 69 has been eliminated since this area is not necessary to define the high pressure loading zone of the wear plate. The groove 77a, elastomer t 80a and seal 81a of FIGURES 13 and 16 substantially surround the bores 68a and 69a which accommodate the journals of the gears and, as illustrated in FIGURE 13, may extend approximately 270 around the bores 68a and 69a and the gear journals. However, when the W shaped construction is utilized, an additional seal 95 may be used. The seal 95 comprising an elastomeric or resilient sealing member assembled within a groove 96. The additional seal 95 is necessary in this construction to prevent any high pressure fluid around the journals 16 of the gears 13 and 14 from leaking to the inlet side of the pump across the face of the wear plate 30a in the area of the seal 95 as will be clear from the drawings. The W shaped seal of wear plate 3% defines generally an identical high pressure zone 91 on the wear plate as does the construction of FIGURE 30. Thus the modified wear plate 30a will function in a like manner to the wear plate 30 as described above.

From the above it will be apparent that the present invention provides a novel and improved pressure loaded pump structure which has numerous advantages and unexpected results in the pressure loaded pump field due to the use of the grooves 77 and the structure therewithin. Fluid pressure is utilized to define a high pressure loading zone by providing a loading force on the seal of the wear plate defining the zone. Further, the pressure utilized to provide a sealing force within the area of grooves 77 also aids in the pressure loading function in that additional force will also be applied to the wear plate to move same into contact with the side faces of the gears.

Also, a resilient member or elastomer has been utilized which in pump assembly is slightly compressed and inherently provides a preloading function on the wear plate 30 to initially move the wear plate into engagement with the gears and provide a sealing engagement between the gears and the wear plate to improve pump efiiciency during initial pumping stage.

Further, the shape of the improved wear plate of the present invention has been designed so as to provide a fool-proof assembly feature in that the wear plate must be assembled within the cavity in the proper orientation or assembly is not possible.

Further, the improved wear plate has a relieved outer surface over a great extent thereof in the high pressure zone to eliminate the pressure gradient problem normally involved in pressure loaded pumps and minimize same.

In the construction of the present invention the pressure loading seal structure is a part of and carried with the wear plate of the pump. Thus complicated machining within the pump body is eliminated since the wear plate may be machined and the pressure loading and sealing structures carried therewith assembled to the wear plate before the wear plate is assembled to the pump.

Further, the improved pump design of the present invention includes inlet recesses in both the pump cover and the wear plate to provide a smooth and continuous flow of fluid to the pump gears and outlet recesses are provided in both the wear plate 30 and the pump cover to serve as anti-trapping grooves or recesses to prevent high pressure fluid from being trapped between the gears and thereby improve pump efficiency. Arcuate recesses 47 in the pump cover which connect to the outlet recess 46 further improve pump efliciency in reducing the torque required to operate the pump since the recesses 47 extend approximately 107 around the circumference of the pumping gears in the area of the gear teeth. The recesses 47 extend in a radial sense from the root of the teeth of the pumping gears to the outer diameter of the gear teeth and thus a substantial area of the pump cover which normally has frictional engagement with the pump gears has been relieved to substantially reduce the frictional losses within the pump.

The present invention comprising the improved wear plate 30 can be used in pumps having a wear plate on each side of the gears. The principle of operation of the wear plate in providing pressure loading when two are used is similar to that described above for a single wear plate pump. However in the two wear plate construction advantages are apparent in that less accuracy of machining is required when the sealing and pressure loading described above is provided on each side of the pump gears. Various of the features of the invention have been particularly shown and described; however, it should be ob- VlOUS to one skilled in the art that various modifications maybe made therein without departing from the scope of the invention.

We claim: 1. An hydraulic apparatus comprising: a housing having a cavity and a pair of end Walls; a pair of rotatable means having sides thereon disposed in said cavity; means defining an inlet and an outlet in said housing leading to and from said rotatable means whereby said rotatable means receives fluid from said inlet and delivers a certain fluid pressure out said outlet; a one-piece plate disposed in said cavity between one of said end walls and said pair of rotatable means, said plate having opposed faces; said plate being movable toward said pair of rotatable means to provide a sealing engagement between one of said faces and said pair of rotatable means, a groove in the other face of said plate having a resilient means therein, a sealing member in said groove engageable by said resilient means, said sealing member being engageable with said one end wall to define a pressure chamber, said chamber being in communication with the pressure in said outlet whereby said pressure in said chamber maintains said plate in engagement with said rotatable means, and means in said plate communicating pressure in said chamber with said groove whereby said pressure will act in said groove to deform said resilient means and thereby urge said sealing member outwardly with respect to said plate to maintain a sealing engagement between said sealing member and said end wall, and wherein said pair of rotatable means comprises a pair of gears each having a journal extending through said plate, said sealing means, resilient member and groove each having a generally spectacle like shape and thereby substantially surrounding each of said journals.

2. An hydraulic apparatus as claimed in claim 1 wherein said resilient means includes preloading means integral therewith and adapted to initially move said sealing member into engagement with said end wall before said hydraulic apparatus is in operation and delivering fluid pressure.

3. An hydraulic apparatus as claimed in claim 2 wherein said preloading means comprises: a plurality of projections on one side of said resilient means adapted to engage said plate within said groove to provide an initial separating force between said plate and said sealing member.

4. An apparatus as claimed in claim 2 wherein said resilient means has a generally rectangular cross-section.

5. An apparatus as claimed in claim 4 wherein said preload means comprises a plurality of conically shaped projections extending from said resilient means and contacting said plate within said groove.

6. An apparatus as claimed in claim 1 wherein said resilient member has a channel therein cooperating with said groove to form a passage to conduct fluid pressure along the length of said resilient member.

7. An apparatus as claimed in claim 1 wherein said resilient member comprises an elastomer.

8. An apparatus as claimed in claim 1 wherein said sealing member is flexible.

9. An hydraulic apparatus as claimed in claim 1 wherein said plate has a generally arcuate circumferate surface generally complimentary to said cavity, said surface being relieved except for two arcuate locating portions thereof to allow for relatively free axial movement of said plate within said cavity.

10. An assembled structure including a fluid seal comprising a surface and a member adjacent said surface, means cooperating with said surface comprising a source of fluid pressure, a groove in said member, a resilient member mounted in said groove, a sealing member within said groove and in engagement with said resilient member, means communicating said pressure to said groove whereby said resilient member will be deformed and urge said sealing member into sealing engagement with said surface, preload means integral with said resilient means comprising a plurality of deformable conical projections on said resilient means, said projections being deformed when said structure is assembled whereby said sealing member will be initially urged into engagement with said surface prior to supply of fluid pressure from said source.

11. An hydraulic apparatus as claimed in claim 1 wherein said housing cavity is defined by an inner peripheral surface and said pair of end walls; said plate having bores therein, said journals passing through said bores, means defining a clearance between said bores and said journals, said plate being movable transversely toward said inner peripheral surface to provide a sealing engagement between said plate and said surface and axially toward said rotatable means.

12. An hydraulic apparatus comprising: a housing having a cavity and a pair of end walls; a pair of rotatable means having sides thereon disposed in said cavity; means defining an inlet and an outlet in said housing leading to and from said rotatable means whereby said rotatable means receives fluid from said inlet and delivers a certain fluid pressure out said outlet; a one-piece plate disposed in said cavity between one of said end walls and said pair of rotatable means, said plate having opposed faces; said plate being movable toward said pair of rotatable means to provide a sealing engagement between one of said faces and said pair of rotatable means, a groove in the other face of said plate having a sealing member therein, said sealing member being engageahle with said one end wall to define a pressure chamber, said chamber being in com- 'munication with the pressure in said outlet whereby said pressure in said chamber maintains said plate in engagement with said rotatable means, and means in said plate communicating pressure in said chamber with said groove whereby said pressure will act in said groove to urge said sealing member outwardly with respect to said plate to maintain a sealing engagement between said sealing member and said end wall and wherein said pair of rotatable means comprises a pair of gears each having a journal extending through said plate, said sealing member and groove each having a generally spectacle like shape and thereby substantially surrounding each of the said journals.

References Cited UNITED STATES PATENTS 2,714,856 8/1955 Kane 103126 2,809,592 10/1957 Miller et al. 103126 2,816,512 12/1957 Murray 103126 2,853,952 5/1958 Aspelin 103l26 2,933,047 4/1960 Judkins 103-126 3,068,804 12/1962 Thrap et al 103-126 3,104,616 9/1963 Peet 103126 3,137,238 6/1964 Gordon 103-126 3,142,260 7/1964 Oliver 103-l26 3,213,799 10/1965 Trick 103126 3,294,029 12/1966 Clark et al. 103126 DONLEY J. STOCKING, Primary Examiner.

WILBUR I. GOODLIN, Examiner. 

